Apparatus and method for coding packet

ABSTRACT

An apparatus for coding a plurality of packets in a multi-antenna system, the apparatus including a processor configured to determine space-time codes of the plurality of packets sequentially from a subsequent packet to maximize an average throughput of the plurality of packets, and a transmitter configured to transmit the plurality of packets to an antenna, is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the US National stage, under 35 U.S.C. § 371, ofInternational App. No. PCT/KR2016/002122 which was filed on Mar. 3, 2016and claims priority to Korean Application No. 10-2016-0025141 filed Mar.2, 2016 and Korean Application No. 10-2015-0032678 filed Mar. 9, 2015.

TECHNICAL FIELD

Embodiments relate to packet coding technology, and more particularly,to technology that performs coding to optimize a throughput bydetermining space-time codes of packets in a multi-antenna wirelesscommunication system.

BACKGROUND ART OF THE INVENTION

The number of possible cases for dividing a hierarchical multimediasource into a number of packets and assigning a separate space-time codeto each packet to be transmitted is M^(Np).

In M^(Np), M denotes the number of types of assignable space-time codes,and Np denotes the number of packets. Among the M^(Np) possible cases, acase that maximizes an average throughput of the multimedia source needsto be determined. As learned from the foregoing, the number of cases forassigning increases exponentially as the number of packets increases.

To optimize packet transmission, throughputs for all the M^(Np) casesfor assigning are calculated numerically, and a case with a maximumthroughput is selected. Thus, a great computational complexity isneeded.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided anapparatus for coding a plurality of packets in a multi-antenna system,the apparatus including a processor configured to determine space-timecodes of the plurality of packets sequentially from a subsequent packetto maximize an average throughput of the plurality of packets, and atransmitter configured to transmit the plurality of packets to anantenna.

The processor may be configured to determine the space-time codessequentially from a last packet to a first packet. The averagethroughput may be expressed using a packet error rate and a datatransmission rate of each packet. The space-time codes may be associatedwith a multi-antenna wireless communication system. The plurality ofpackets may be associated with a hierarchical multimedia source. Thehierarchical multimedia source may be associated with a scalable videoor a progressive image.

According to another aspect of the present invention, there is alsoprovided a method of coding a plurality of packets in a multi-antennasystem, the method including determining space-time codes of theplurality of packets sequentially from a subsequent packet to maximizean average throughput of the plurality of packets, and transmitting theplurality of packets to an antenna.

The method may further include determining the space-time codessequentially from a last packet to a first packet.

The method may further include expressing the average throughput using apacket error rate and a data transmission rate of each packet. Themethod may further include associating the space-time codes with amulti-antenna wireless communication system. The plurality of packetsmay be associated with a hierarchical multimedia source.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a packet coding apparatusaccording to an embodiment.

FIG. 2 is a graph illustrating packet error rates of space-time codesaccording to an embodiment.

FIG. 3 is a diagram illustrating a method of maximizing an averagethroughput according to an embodiment.

FIG. 4 is a graph illustrating average throughputs with respect tospace-time codes according to an embodiment.

FIG. 5 is a flowchart illustrating an algorithm of a packet codingmethod according to an embodiment.

FIG. 6 is a flowchart illustrating an algorithm of a packet codingmethod according to another embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Specific structural or functional descriptions of embodiments are merelydisclosed as examples, and may be variously modified and implemented.Thus, the embodiments are not limited, and it is intended that variousmodifications, equivalents, and alternatives are also covered within thescope of the present disclosure.

Although terms of “first”, “second”, etc. are used to explain variouscomponents, the components are not limited to such terms. These termsare used only to distinguish one component from another component. Forexample, a first component may be referred to as a second component, orsimilarly, the second component may be referred to as the firstcomponent.

When it is mentioned that one component is “connected” or “accessed” toanother component, it may be understood that the one component isdirectly connected or accessed to another component or that still one ofmore other components is interposed between the two components.

A singular expression includes a plural concept unless there is acontextually distinctive difference therebetween. Herein, the term“include” or “have” is intended to indicate that characteristics,numbers, steps, operations, components, elements, etc. disclosed in thespecification or combinations thereof exist. As such, the term “include”or “have” should be understood to mean that there are additionalpossibilities of one or more other characteristics, numbers, steps,operations, components, elements or combinations thereof.

Unless specifically defined, all the terms used herein includingtechnical or scientific terms have the same meaning as terms generallyunderstood by those skilled in the art. Terms defined in a generaldictionary should be understood so as to have the same meanings ascontextual meanings of the related art. Unless definitely definedherein, the terms are not interpreted as having ideal or excessivelyformal meanings. Hereinafter, embodiments will be described in detailwith reference to the accompanying drawings. Like reference numerals inthe drawings denote like elements.

FIG. 1 is a block diagram illustrating a packet coding apparatusaccording to an embodiment.

Referring to FIG. 1, a packet coding apparatus 100 may include aprocessor 110, and a transmitter 120. The processor 110 may determinespace-time codes of a plurality of packets to be transmitted,sequentially from a subsequent packet, to maximize an average throughputof the plurality of packets. The transmitter 120 may transmit theplurality of packets to an antenna.

Due to characteristics of a hierarchical multimedia, the hierarchicalmultimedia is transmitted in a form of flow of data transmittedconsecutively through a series communication line, in detail, one bit ata time. In this example, in an aspect of overall packet validation, whenan error occurs in a previously transmitted packet, packets subsequentto the corresponding packet may not be used for decoding although thesubsequent packets are transmitted without error. In detail, a priorpacket needs to be transmitted without error to transmit subsequentpackets without error. Thus, by determining separate space-time codes ofpackets, sequentially from a subsequent packet to a relativelysignificant prior packet or in an inverse order, transmission of amultimedia source may be optimized. Hereinafter, for ease ofdescription, an example of transmitting a multimedia source includingfour packets is provided. However, embodiments are not limited thereto.The embodiments are also applicable to an example of transmitting agreater number of packets. An average throughput when transmitting fourpackets may be expressed by Equation 1, which is also shown in a box 310of FIG. 3.ATP=R ₁(1−P ₁)P ₂+(R ₁ +R ₂)(1−P ₁)(1−P ₂)P ₃+(R ₁ +R ₂ +R ₃)(1−P ₁)(1−P₂)(1−P ₃)P ₄+(R ₁ +R ₂ +R ₃ +R ₄)(1−P ₁)(1−P ₂)(1−P ₃)(1−P ₄)  [Equation1]

In an apparatus for coding a plurality of packets in a multi-antennasystem, the average throughput of the multimedia may be expressed usinga packet error rate and a data transmission rate of each packet. InEquation 1, ATP stands for an average throughput, R_(i) (bits) denotes adata transmission rate of each packet or a size of a packet, and P_(i)denotes a packet error rate. The first term is related to the number ofcases in which a first packet with a size of R₁ is transmitted with aprobability of (1−P₁) and an error occurs in a second packet with aprobability of P₂. Similarly, the second term is related to the numberof cases in which the first packet and the second packet (R₁+R₂) aretransmitted with probabilities of (1−P₁) and (1−P₂) and an error occursin a third packet with a probability of P₃. Similarly, by calculatingthe third term and the fourth term, the average throughput may becalculated. In space-time coding used in a multi-antenna system, forexample, a multiple-input multiple-output (MIMO) system, an overallaverage throughput may vary based on a space-time code to be determinedwith respect to a packet, as learned in Equation 1. In a related art,calculation is performed with respect to all cases for a space-time codethat maximizes the average throughput, and thus a processor may beoverloaded. However, when a packet coding method provided herein isused, such overload may be prevented. R_(i) and P_(i) in Equation 1 varybased on a space-time code to be determined for a packet, and there is atrade-off between R_(i) and P_(i). Thus, it is difficult to determine aspace-time code that maximizes the overall average throughput.Hereinafter, the trade-off will be described with reference to FIG. 2.

FIG. 2 is a graph illustrating packet error rates of space-time codesaccording to an embodiment.

In an apparatus for coding a plurality of packets in a multi-antennasystem, a space-time code may be associated with a multi-antennawireless communication system. In general, space-time coding has atrade-off between a data transmission rate and a packet error rate.Herein, descriptions will be provided based on space-time codes oforthogonal space-time block code (OSTBC), double-space time transmitdiversity (D-STTD), and vertical-bell laboratories layered space-time(V-BLAST) which are widely used. However, embodiments are not limitedthereto. The embodiments are applicable to all space-time codes. Atrade-off between a data transmission rate and a packet error rate ofeach space-time code in a 4×4 MIMO system including four transmitantennas and four receive antennas is shown in Table 1. A relationshipbetween a packet error rate and a signal-to-noise ratio (SNR) per symbolis shown in the graph of FIG. 2.

TABLE 1 Data transmission rate (Ri) Packet error rate (Pi) OSTBC Low(1.5 bits/sec/Hz) Low D-STTD Middle (4 bits/sec/Hz) Middle V-BLAST High(4 bits/sec/Hz) High

In detail, since the packet error rate P_(i) increases as the datatransmission rate R_(i) increases, it may not be easy to determine anoptimal space-time code to be assigned to a predetermined packet. Whenassigning three space-time codes of OSTBC, D-STTD, and V-BLAST to thefour packets suggested above, the number of possible cases is “81”. Aspace-time coding scheme provided herein may dramatically reduce thenumber of cases without performing such an exhaustive search, which willbe described in detail with reference to FIG. 3.

FIG. 3 is a diagram illustrating a method of maximizing an averagethroughput according to an embodiment.

In an apparatus for coding a plurality of packets in a multi-antennasystem, a processor may determine space-time codes of the plurality ofpackets sequentially from a last packet to a first packet. Bydetermining the space-time codes sequentially from the last packet andperforming the same process to the first packet, the number of cases maybe dramatically reduced when compared to an existing algorithm. In theexisting algorithm, the number of cases increases exponentially as thenumber of packets and the number of space-time codes increase. However,herein, the number of cases may be reduced by a product of the number ofpackets and the number of space-time codes. To investigate the foregoingmethod in detail, Equation 1 may be arranged with respect to R₄ asexpressed by Equation 2, which is also shown in a box 320 of FIG. 3.ATP=R ₄(1−P ₁)(1−P ₂)(1−P ₃)(1−P ₄)+R ₃(1−P ₁)(1−P ₂)(1−P ₃)+R ₂(1−P₁)(1−P ₂)+R ₁(1−P ₁)  [Equation 2]

When Equation 1 is arranged as shown in Equation 2, a space-time code tobe used for the last packet, for example, the fourth packet in Equation2, may be determined among various space-time codes, for example, threespace-time codes of OSTBC, D-STTD, and V-BLAST. Variables related to thefourth packet in Equation 2 are R₄ and P₄, and values related to theother packets may be regarded as constants. In detail, R₄ and P₄ may bedetermined based on the space-time code to be used for the fourthpacket, and thus a space-time code that maximizes ATP of Equation 2 maybe determined.

Here, it may be learned from Equation 2 that R₃, P₃, R₂, P₂, R₁, and P₁do not need to be determined yet when determining R₄ and P₄. In detail,irrespective of space-time codes to be assigned to the first, second,and third packets, the space-time code of the fourth packet to maximizeATP may be determined.

To determine a code of the third packet, Equation 1 may be arrangedsimilarly as expressed by Equation 3, which is also shown in a box 330of FIG. 3.ATP=(1−P ₁)(1−P ₂){R ₄(1−P ₄)(1−P ₃)+R ₃(1−P ₃)}+R ₂(1−P ₂)(1−P ₁)+R₁(1−P ₁)  [Equation 3]

When the space-time code of the last packet is determined, a space-timecode to be used for a packet prior to the last packet, for example, thethird packet in the above example, may be determined. In detail, in thesituation in which R₄ and P₄ are determined based on the space-time codedetermined in the previous operation, the space-time code of the thirdpacket to maximize the average throughput may be determined. Here, itmay also be learned that R₂, P₂, R₁, and P₁ do not need to be determinedyet when determining R₃ and P₃. Irrespective of space-time codes to beassigned to the first and second packets, the space-time code of thethird packet to maximize the average throughput may be determined whiledata transmission rates and the space-time codes of the first and secondpackets are regarded as constants.

To determine a code of the second packet, Equation 1 may be arrangedsimilarly as expressed by Equation 4, which is also shown in a box 340of FIG. 3.ATP=(1−P ₁){R ₄(1−P ₄)(1−P ₃)(1−P ₂)+R ₃(1−P ₃)(1−P ₂)+R ₂(1−P ₂)}+R₁(1−P ₁)  [Equation 4]

In Equation 4, a space-time code to be used for packet prior to thethird packet, for example, the second packet in the above example, maybe determined. In detail, in the situation in which R₄, P₄, R₃, and P₃are determined based on the space-time codes determined in the previousoperations, the space-time code of the second packet to maximize theaverage throughput may be determined. Similarly, R₁ and P₁ do not needto be determined yet when determining R₂ and P₂, and may be regarded asconstants. In detail, irrespective of a space-time code to be assignedto the first packet, the space-time code of the second packet tomaximize the average throughput may be determined. When the space-timecode of the second packet is determined, a space-time code of the firstpacket to maximize the average throughput may be determined finally.

In the apparatus for coding a plurality of packets in the multi-antennasystem, the plurality of packets may be associated with a hierarchicalmultimedia source. The multimedia source may be associated with ascalable video or a progressive image. The hierarchical multimediasource may be associated with a multimedia to be coded hierarchically.Hierarchical coding refers to a qualitative hierarchy-based codingscheme in which a lowermost hierarchy contains minimum information andsucceeding hierarchies contain more information in a qualitative aspect.Such a compression scheme is effective for a packet exchange networkwhere network resources are shared between a number of traffic streams,and delays and losses are expected. Due to such characteristics of thehierarchical multimedia, the hierarchical multimedia is transmitted in aform of flow of data transmitted consecutively through a seriescommunication line, in detail, one bit at a time. Thus, by applying thepacket coding method provided herein, a load of the processor may bereduced. Scalable video coding (SVC) is a name for the Annex G extensionof H.264/MPEG-4 AVC (a family of block-oriented motion-compensationstandards for the recording, compression, and distribution of videocontent developed by the Moving Picture Experts Group-4, Advanced VideoCoding) video compression standard. SVC may be used to encode ahigh-quality video bitstream including one or more subset bitstreams. Asubset bitstream may represent a relatively low spatial resolution(relatively small screen), relatively low temporal resolution(relatively low frame rate), or relatively low-quality video signal. Byperforming SVC using the packet coding apparatus suggested herein, amultimedia to be used for standard-definition television (SDTV) anddigital multimedia broadcasting (DMB) may be coded. Progressive imagetransmission refers to a scheme of progressively transmitting a portionof image data, rather than transmitting the whole image data, which iseffective in interactive image transmission to a user overnarrow-bandwidth channels such as telephone lines. Image data to betransmitted may be coded using various image coding schemes. At first, arough form of an image may be represented, and the image of improvedquality may be progressively restored by transmitting additional data.Such a progressive image may be coded and transmitted based on ahierarchical multimedia, and thus the packet coding apparatus suggestedherein may be used for coding the progressive image.

FIG. 4 is a graph illustrating average throughputs with respect tospace-time codes according to an embodiment.

The graph of FIG. 4 illustrates throughputs of space-time codes whenOSTBC, D-STTD, or V-BLAST is used solely or a combination thereof isused in a 4×4 MIMO system. JSCC in FIG. 4 is an abbreviation for “JointSource Channel Coding: OSTBC, D-STTD, and V-BLAST each includes a periodin which an average throughput is maximized, when compared to the otherspace-time codes. Thus, by determining a space-time code of a packetusing all of OSTBC, D-STTD, and V-BLAST, the throughput may bemaximized.

For example, the number of cases of assigning three space-time codes tosixteen packets is 3¹⁶. A result of applying a packet coding algorithmprovided herein and an exhaustive search to determine space-time codesto be assigned to maximize an ATP by comparing ATPs of the 3¹⁶ possiblecases is shown in Table 2, and the same result may be obtained.

TABLE 2 SNR(dB) (1: OSTBC, 2: D-STTD, 3: V-BLAST) 8 1 1 1 1 1 1 1 1 1 11 1 1 2 2 2 10 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 12 2 2 2 2 2 2 2 2 2 2 22 2 2 2 2 14 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 16 2 2 2 3 3 3 3 3 3 3 3 33 3 3 3

When the scheme suggested herein is used, average throughputs of only16×3=48 cases in total need to be compared, and thus a computationalcomplexity may be reduced. In detail, the present disclosure may performoptimized coding when a wireless communication system transmits aprogressive image or a scalable video which is a hierarchical multimediasource including a number of packets, thereby considerably reducing acomputational complexity for determining a space-time coding scheme tobe applied to each packet. In particular, a great computationalcomplexity is needed for assigning optimal space-time codes to a largenumber of packets in real time. Thus, the present disclosure may greatlycontribute to implementation of an effective real-time multimediatransmission system.

FIG. 5 is a flowchart illustrating an algorithm of a packet codingmethod according to an embodiment. FIG. 6 is a flowchart illustrating analgorithm of a packet coding method according to another embodiment.

Referring to FIG. 6, in operation 610, a packet coding method maydetermine space-time codes of a plurality of packets sequentially from asubsequent packet to maximize an average throughput of the plurality ofpackets. In operation 620, the packet coding method may transmit theplurality of packets to an antenna. Referring to FIG. 5, the packetcoding method may be used to hierarchically code a multimedia. Due tocharacteristics of a hierarchical multimedia, the hierarchicalmultimedia is transmitted in a form of flow of data transmittedconsecutively through a series communication line, in detail, one bit ata time. In this example, in an aspect of overall packet validation, whenan error occurs in a previously transmitted packet, packets subsequentto the corresponding packet may not be used for decoding although thesubsequent packets are transmitted without error. In detail, a priorpacket needs to be transmitted without error to transmit subsequentpackets without error. Thus, by determining separate space-time codes ofpackets, sequentially from a subsequent packet to a relativelysignificant prior packet or in an inverse order, transmission of amultimedia source may be optimized.

As described above, to transmit n packets, a method of determiningspace-time codes of the n packets sequentially from a last packet tomaximize an average throughput may be used. The space-time codes maycorrespond to space-time codes of OSTBC, D-STTD, and V-BLAST. However,embodiments are not limited thereto.

In a method of coding a plurality of packets in a multi-antenna system,the average throughput of the multimedia may be expressed using a packeterror rate and a data transmission rate of each packet. In space-timecoding used in a multi-antenna system, for example, a MIMO system, anoverall average throughput may vary based on a space-time code to bedetermined with respect to a packet. In the related art as describedabove, calculation is performed with respect to all cases for aspace-time code that maximizes the average throughput, and thus aprocessor may be overloaded. However, when a packet coding methodprovided herein is used, such overload may be prevented. However, R_(i)denoting a data transmission rate of a packet and P_(i) denoting apacket error rate of the packet vary based on a space-time code to bedetermined for a packet, and there is a trade-off between R_(i) andP_(i). Thus, it is difficult to determine a space-time code thatmaximizes the overall average throughput.

In the method of coding a plurality of packets in the multi-antennasystem, a space-time code may be associated with a multi-antennawireless communication system. In general, space-time coding has atrade-off between a data transmission rate and a packet error rate. Indetail, when the data transmission rate R_(i) increases, the packeterror rate P_(i) also increases. Thus, it may not be easy to determinean optimal space-time code to be assigned to a predetermined packet. Forexample, when m space-time codes are to be assigned to n packets, thenumber of possible cases is m^(n). The space-time coding scheme providedherein may dramatically reduce the number of cases by m×n, withoutperforming the exhaustive search described above.

In an apparatus for coding a plurality of packets in a multi-antennasystem, the processor may determine space-time codes of the plurality ofpackets sequentially from a last packet to a first packet. Referring toFIG. 5, when n packets are to be transmitted, the packet codingapparatus may determine a space-time code of an n-th packet, inoperation 501. In this example, similarly, a space-time code thatmaximizes the average throughput may be determined. When the space-timecode of the n-th packet is determined, the packet coding apparatus maydetermine a space-time code of an (n−1)-th packet, in operation 502. Bycontinuously performing the same process, the packet coding apparatusmay determine a space-time code of a first packet, in operation 503. Inan existing method, the number of cases increases exponentially as thenumber of packets and the number of space-time codes increase. However,when the foregoing method is used, the number of cases may be reduced bya product of the number of packets and the number of space-time codes.In this example, when the space-time code is determined, space-timecodes of the other packets may be regarded as constants, whereby theaverage throughput may be maximized. When the space-time codes of thepackets are determined, the packet coding apparatus may verify whetherthe average throughput is maximized, in operation 510. When the averagethroughput is maximized, the packet coding apparatus may transmit the npackets to an antenna, in operation 520. Conversely, when the averagethroughput is not maximized, the packet coding apparatus may repeat theoperation of determining space-time codes sequentially from the lastpacket, for example, the n-th packet. Through the feedback, optimalspace-time codes may be determined. In detail, according to embodiments,optimized coding may be performed when transmitting a progressive imageor a scalable video which is a hierarchical multimedia source includinga number of packets in a wireless communication system, whereby acomputational complexity for determining a space-time coding scheme tobe applied to each packet may be greatly reduced.

In the method of coding a plurality of packets in the multi-antennasystem, the plurality of packets may be associated with a hierarchicalmultimedia source. The multimedia source may be associated with ascalable video or a progressive image. The hierarchical multimediasource may be associated with a multimedia to be coded hierarchically.Hierarchical coding refers to a qualitative hierarchy-based codingscheme in which a lowermost hierarchy contains minimum information andsucceeding hierarchies contain more information in a qualitative aspect.Such a compression scheme is effective for a packet exchange networkwhere network resources are shared between a number of traffic streams,and delays and losses are expected. Due to such characteristics of thehierarchical multimedia, the hierarchical multimedia is transmitted in aform of flow of data transmitted consecutively through a seriescommunication line, in detail, one bit at a time. Thus, by applying thepacket coding method provided herein, a load of the processor may bereduced. SVC is a name for the Annex G extension of H.264/MPEG-4 AVCvideo compression standard. SVC may be used to encode a high-qualityvideo bitstream including one or more subset bitstreams. A subsetbitstream may represent a relatively low spatial resolution (relativelysmall screen), relatively low temporal resolution (relatively low framerate), or relatively low-quality video signal. By performing SVC usingthe packet coding apparatus suggested herein, a multimedia to be usedfor SDTV and DMB may be coded. Progressive image transmission refers toa scheme of progressively transmitting a portion of image data, ratherthan transmitting the whole image data, which is effective ininteractive image transmission to a user over narrow-bandwidth channelssuch as telephone lines. Image data to be transmitted may be coded usingvarious image coding schemes. At first, a rough form of an image may berepresented, and the image of improved quality may be progressivelyrestored by transmitting additional data. Such a progressive image maybe coded and transmitted based on a hierarchical multimedia, and thusthe packet coding apparatus suggested herein may be used for coding theprogressive image. Detailed descriptions of the packet coding method arethe same as the descriptions of the packet coding apparatus, and thusduplicated descriptions will be omitted for conciseness.

The units and/or modules described herein may be implemented usinghardware components and software components. For example, the hardwarecomponents may include microphones, amplifiers, band-pass filters, audioto digital converters, and processing devices. A processing device maybe implemented using one or more hardware devices configured to carryout and/or execute program code by performing arithmetical, logical, andinput/output operations. The processing device(s) may include aprocessor, a controller and an arithmetic logic unit, a digital signalprocessor, a microcomputer, a field programmable array, a programmablelogic unit, a microprocessor or any other device capable of respondingto and executing instructions in a defined manner. The processing devicemay run an operating system (OS) and one or more software applicationsthat run on the OS. The processing device also may access, store,manipulate, process, and create data in response to execution of thesoftware. For purposes of simplicity, the description of a processingdevice is described in the singular; however, one skilled in the artwill appreciate that a processing device may include multiple processingelements and multiple types of processing elements. For example, aprocessing device may include multiple processors or a processor and acontroller. In addition, different processing configurations arepossible, such as parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, to independently orcollectively instruct and/or configure the processing device to operateas desired, thereby transforming the processing device into a specialpurpose processor. Software and data may be embodied permanently ortemporarily in any type of machine, component, physical or virtualequipment, computer storage medium or device, or in a propagated signalwave capable of providing instructions or data to or being interpretedby the processing device. The software also may be distributed overnetwork coupled computer systems so that the software is stored andexecuted in a distributed fashion. The software and data may be storedby one or more non-transitory computer readable recording mediums.

The methods according to the above-described example embodiments may berecorded in non-transitory computer-readable media including programinstructions to implement various operations of the above-describedexample embodiments. The media may also include, alone or in combinationwith the program instructions, data files, data structures, and thelike. The program instructions recorded on the media may be thosespecially designed and constructed to provide example embodiments, orthey may be of the kind well-known and available to those having skillin the computer software arts. Examples of non-transitorycomputer-readable media include magnetic media such as hard disks,floppy disks, and magnetic tape; optical media such as CD-ROM discs,DVDs, and/or Blue-ray discs; magneto-optical media such as opticaldiscs; and hardware devices that are specially configured to store andperform program instructions, such as read-only memory (ROM), randomaccess memory (RAM), flash memory (e.g., USB flash drives, memory cards,memory sticks, etc.), and the like. Examples of program instructionsinclude both machine code, such as produced by a compiler, and filescontaining higher level code that may be executed by the computer usingan interpreter. The above-described devices may be configured to act asone or more software modules in order to perform the operations of theabove-described example embodiments, or vice versa.

A number of example embodiments have been described above. Nevertheless,it should be understood that various modifications may be made to theseexample embodiments. For example, suitable results may be achieved ifthe described techniques are performed in a different order and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Accordingly, other implementations arewithin the scope of the following claim.

The invention claimed is:
 1. An apparatus for coding a plurality ofpackets in a multi-antenna system associated with a hierarchicalmultimedia source, the apparatus comprising: a processor configured todetermine space-time codes of the plurality of packets associated withthe hierarchical multimedia source, using an average throughput (ATP)expressed according to the following Equation:ATP=R ₁(1−P ₁)P ₂+(R ₁ +R ₂)(1−P ₁)(1−P ₂)P ₃+(R ₁ +R ₂ +R ₃)(1−P ₁)(1−P₂)(1−P ₃)P ₄+ . . . +(R ₁ +R ₂ +R ₃ + . . . +R _(n−1))(1−P ₁)(1−P ₂)(1−P₃) . . . (1−P _(n−1))P _(n)+(R ₁ +R ₂ +R ₃ + . . . +R _(n)−1+R _(n))(1−P₁)(1−P ₂)(1−P ₃) . . . (1−P _(n−1))(1−P _(n)) wherein R₁, R₂ . . .R_(n−1) and R_(n) denote a data transmission rate of each packet or sizeof packet to be transmitted; P₁, P₂ . . . P_(n−1) and P_(n) denote apacket error rate of each packet to be transmitted; ‘n’ denotes thenumber of packets to be transmitted, wherein, the processor is to verifywhether the average throughput of the plurality of packets is maximizedwhen the space-time codes of the packets are determined; and atransmitter configured to transmit the plurality of coded packets to anantenna.
 2. The apparatus of claim 1, wherein the space-time codes areassociated with a multi-antenna wireless communication system.
 3. Theapparatus of claim 1, wherein the plurality of packets is associatedwith a scalable video or a progressive image.
 4. A method of coding aplurality of packets in a multi-antenna system associated with ahierarchical multimedia source, the method comprising: determiningspace-time codes of the plurality of packets associated with thehierarchical multimedia source, using an average throughput (ATP)expressed according to the following Equation:ATP=R ₁(1−P ₁)P ₂+(R ₁ +R ₂)(1−P ₁)(1−P ₂)P ₃+(R ₁ +R ₂ +R ₃)(1−P ₁)(1−P₂)(1−P ₃)P ₄+ . . . +(R ₁ +R ₂ +R ₃ + . . . +R _(n−1))(1−P ₁)(1−P ₂)(1−P₃) . . . (1−P _(n−1))P _(n)+(R ₁ +R ₂ +R ₃ + . . . +R _(n)−1+R _(n))(1−P₁)(1−P ₂)(1−P ₃) . . . (1−P _(n−1))(1−P _(n)) wherein R₁, R₂ . . .R_(n−1) and R_(n) denote a data transmission rate of each packet or sizeof packet to be transmitted; P₁, P₂ . . . P_(n−1) and P_(n) denote apacket error rate of each packet to be transmitted; ‘n’ denotes thenumber of packets to be transmitted, verifying whether the averagethroughput of the plurality of packets is maximized when the space-timecodes of the packets are determined; and transmitting the plurality ofcoded packets to an antenna.
 5. The method of claim 4, furthercomprising: associating the space-time codes with a multi-antennawireless communication system.
 6. The method of claim 4, wherein theplurality of packets is associated with a scalable video or aprogressive image.
 7. A non-transitory computer-readable mediumcomprising a program for instructing a computer to perform a method ofcoding a plurality of packets in a multi-antenna system associated witha hierarchical multimedia source, the method comprising: determiningspace-time codes of the plurality of packets associated with thehierarchical multimedia source, using an average throughput (ATP)expressed according to the following Equation:ATP=R ₁(1−P ₁)P ₂+(R ₁ +R ₂)(1−P ₁)(1−P ₂)P ₃+(R ₁ +R ₂ +R ₃)(1−P ₁)(1−P₂)(1−P ₃)P ₄+ . . . +(R ₁ +R ₂ +R ₃ + . . . +R _(n−1))(1−P ₁)(1−P ₂)(1−P₃) . . . (1−P _(n−1))P _(n)+(R ₁ +R ₂ +R ₃ + . . . +R _(n)−1+R _(n))(1−P₁)(1−P ₂)(1−P ₃) . . . (1−P _(n−1))(1−P _(n)) wherein R₁, R₂ . . .R_(n−1) and R_(n) denote a data transmission rate of each packet or sizeof packet to be transmitted; P₁, P₂ . . . P_(n−1) and P_(n) denote apacket error rate of each packet to be transmitted; ‘n’ denotes thenumber of packets to be transmitted, verifying whether the averagethroughput of the plurality of packets is maximized when the space-timecodes of the packets are determined; and transmitting the plurality ofcoded packets to an antenna.
 8. The non-transitory computer-readablemedium of claim 7, wherein the plurality of packets is associated with ascalable video or a progressive image.